Explainer: power station ‘trips’ are normal, but blackouts are not


Hugh Saddler, Australian National University

Tens of thousands of Victorians were left without power over the long weekend as the distribution network struggled with blistering temperatures, reigniting fears about the stability of our energy system.

It comes on the heels of a summer of “trips”, when power stations temporarily shut down for a variety of reasons. This variability has also been used to attack renewable energy such as wind and solar, which naturally fluctuate depending on weather conditions.

The reality is that blackouts, trips and intermittency are three very different issues, which should not be conflated. As most of Australia returns to school and work in February, and summer temperatures continue to rise, the risk of further blackouts make it essential to understand the cause of the blackouts, what a power station “trip” really is, and how intermittent renewable energy can be integrated into a national system.




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Blackouts

Initial reports indicate recent blackouts in Victoria were caused by multiple small failures in the electricity distribution system across the state, affecting all but one of the five separately owned and managed systems that supply Victorians.

Across the whole of mainland Australia, very hot weather causes peak levels of electricity consumption. Unfortunately, for reasons of basic physics, electricity distribution systems do not work well when it is very hot, so the combination of extreme heat and high demand is very challenging. It appears that significant parts of the Victorian electricity distribution system were unable to meet the challenge, leading to uncontrolled blackouts.

Parenthetically, electricity distribution systems are vulnerable to other types of uncontrollable extreme environmental events, including high winds, lightning, and bushfires. Sometimes blackouts last only a few seconds, sometimes for days, depending on the nature and extent of the damage to the system.




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These blackouts are very different from those caused by power station “trips”, although they have the same effect on consumers. When electricity is insufficient to meet demand, certain sections of the grid have to be startegically blacked out to restore the balance (this is known as “load shedding”).

It is the possibility of blackouts of this second type which has excited so much commentary in recent months, and has been linked to power station “trips”.

What is a ‘trip’ and how significant is it?

“Trip” simply means disconnect; it is used to describe the ultra-fast operation of the circuit breakers used as switching devices in high-voltage electricity transmission systems. When a generator trips, it means that it is suddenly, and usually unexpectedly, disconnected from the transmission network, and thus stops supplying electricity to consumers.

The key words here are suddenly and unexpectedly. Consider what happened in Victoria on January 18 this year. It was a very hot day and all three brown coal power stations in the state were generating at near full capacity, supplying in total about 4,200 megawatts towards the end of the afternoon, as total state demand climbed rapidly past 8,000MW (excluding rooftop solar generation).

Suddenly, at 4:35pm, one of the two 500MW units at Loy Yang B, Victoria’s newest (or, more precisely, least old) coal-fired power station tripped. At the time this unit was supplying 490MW, equal to about 6% of total state demand.

The system, under the operational control of the Australia Energy Market Operator (AEMO), responded just as it was meant to. There was considerable spare gas generation capacity, some of which was immediately made available, as was some of the more limited spare hydro capacity. There was also a large increase in imports from New South Wales, and a smaller reduction in net exports to South Australia.

By the time Loy Yang B Unit 1 was fully back on line, three hours later, Victoria had passed its highest daily peak demand for nearly two years. There was no load shedding: all electricity consumers were supplied with as much electricity as they required. However, spot wholesale prices for electricity reached very high levels during the three hours, and it appears that some large consumers, whose supply contracts exposed them to wholesale prices, made short-term reductions in discretionary demand.




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This (relatively) happy outcome on January 18 was made possible by the application of the system reliability rules and procedures, specified in the National Electricity Rules.

These require AEMO to ensure that at all times, in each of the five state regions of the NEM, available spare generation capacity exceeds the combined capacity of the two largest units operating at any time.

In other words, spare capacity must be sufficient to allow demand to continue to be reliably supplied if both of the two largest units generating should suddenly disconnect.

Forecasting

AEMO forecasts energy demand, and issues market notices alerting generators about reliability, demand and potential supply issues. On a busy day, like January 18, market notices may be issued at a rate of several per hour.

These forecasts allowed generators to respond to the loss of Loy Yang B without causing regional blackouts.

What is not publicly known, and may never be known, is why Loy Yang Unit B1 tripped. AEMO examines and reports in detail on what are called “unusual power system events”, which in practice means major disruptions, such as blackouts. There are usually only a few of these each year, whereas generator trips that don’t cause blackouts are much more frequent (as are similar transmission line trips).

It has been widely speculated that, as Australia’s coal fired generators age, they are becoming less reliable, but that could only be confirmed by a systematic and detailed examination of all such events.

Managing variable generation

Finally, and most importantly, the events described above bear almost no relationship to the challenges to reliable system operation presented by the growth of wind and solar generation.

With traditional thermal generation, the problems are caused by unpredictability of sudden failures, and the large unit size, especially of coal generators, which means that a single failure can challenge total system reliability. Individual wind generators may fail unpredictably, but each machine is so small that the loss of one or two has a negligible effect on reliability.

The challenge with wind and solar is not reliability but the variability of their output, caused by variations in weather. This challenge is being addressed by continuous improvement of short term wind forecasting. As day-ahead and hour-ahead forecasts get better, the market advice AEMO provides will give a more accurate estimate of how much other generation will be needed to meet demand at all times.




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Of course, AEMO, and the generation industry, do still get caught out by sudden and unexpected drops in wind speed, but even the fastest drop in wind speed takes much longer than the milliseconds needed for a circuit breaker in a power station switchyard to trip out.

The ConversationAt the same time, as the share of variable renewable generation grows, the complementary need for a greater share of fast response generators and energy storage technologies will also grow, while the value to the system of large, inflexible coal-fired generators will shrink.

Hugh Saddler, Honorary Associate Professor, Centre for Climate Economics and Policy, Australian National University

This article was originally published on The Conversation. Read the original article.

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Trust Me I’m An Expert: Why February is the real danger month for power blackouts


Sunanda Creagh, The Conversation

It’s been hot – and it’s going to get hotter. Australia has experienced some record hot days in recent weeks and scientists say Sydney and Melbourne need to prepare for 50℃ days by the end of the century, or sooner.

In today’s episode of Trust Me I’m An Expert, we’re unpacking the research on why some of the most disadvantaged parts of our cities cop the worst of a heatwave.

And Chris Dunstan, an expert on energy policy, explains why February is the month when energy ministers and energy operators really get worried there won’t be enough electricity to go around – and how you can do your bit to curb blackout risk.

Join us as we ask academic experts to explain the issues making news in Australia.

Trust Me, I’m An Expert is out at the start of every month. Find us and subscribe in Apple Podcasts, Pocket Casts or wherever you get your podcasts.


Further reading

Beyond Coal: Alternatives to extending the life of Liddell power station, by the Institute for Sustainable Futures, UTS.

Explainer: power station ‘trips’ are normal, but blackouts are not

Additional music and audio

Kindergarten by Unkle Ho, from Elefant Traks

Ella Fitzgerald and Louis Armstrong, Summertime.

YACHT: Summer Song (Instrumental) from Free Music Archive

Broke For Free: Summer Spliffs from Free Music Archive

Unheard Music Concepts: Hot Summer Day from Free Music Archive

Ketsa: Summer from Free Music Archive

RT: Sizzling Up: Australian policeman fries egg on car hood in 46°C weather via YouTube

Lateline: Cities need adapt to deadly heatwaves from ABC News

ABC news report

ABC news

The ConversationSeven News, January 8, 2018

Sunanda Creagh, Head of Digital Storytelling, The Conversation

This article was originally published on The Conversation. Read the original article.

The day Australia was put on blackout alert



File 20170906 9830 1ewbtoe
One big mess: the market has failed to deliver on cheap, reliable energy.
Shutterstock

David Blowers, Grattan Institute

The only way the Australian Energy Market Operator (AEMO) could be blunter in its report on the state of our electricity system would be to stick a neon sign on top of its Melbourne head office saying “The market has failed”.

AEMO’s Advice to Commonwealth Government on Dispatchable Capability, released today, shows there are significant but manageable risks of the lights going out in South Australia and Victoria over the next two summers. And beyond 2018, AEMO will need more tools if shortfall risks are going to be dealt with.

The conclusions about the short-term risks are not surprising. AEMO has issued several reports over the past year or so telegraphing supply shortfalls in the next couple of years.

What is surprising is its view that action needs to be taken when Liddell, the AGL-owned power station in New South Wales, closes in 2022. That is five years away, and AGL has been trumpeting the decision at every opportunity, but AEMO is clearly not confident that the market will respond by delivering new generation, or storage, or demand response, to fill the gap.


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AEMO recommends immediate development of a strategic reserve that it can deploy to prevent loss of power over the next few summers. A strategic reserve is basically back-up generation (or storage or demand response) that is used only in an emergency.

AEMO’s job is to make sure there is enough generation available – that supply equals demand. A strategic reserve will deliver the capacity – be it gas generation, storage or demand response – that it needs to meet any shortfall. Neither coal nor wind and solar can fulfil this function. Coal takes too long to come online, while wind and solar provide intermittent supply so there is no certainty that renewable energy will be there when needed.


Read more: Managing demand can save two power stations’ worth of energy at peak times


A strategic reserve is an insurance policy, only to be used in extreme circumstances. And like any insurance policy it has a cost – a cost that will be passed on to consumers. Of course, if electricity keeps being delivered as required over the next two summers, governments and consumers may well consider this money well spent.

But a strategic reserve does not deal with the second problem AEMO is seeking to solve: that not enough dispatchable generation is being built in the National Electricity Market. Even with backup generation controlled by AEMO, Australia will still need new generation to provide day-to-day power when existing power stations such as Liddell close.

AEMO’s second major recommendation is the immediate “development of a longer-term approach to retain existing investment and incentivise new investment in flexible dispatchable capability in the NEM”.


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Since it was set up 20 years ago, the NEM has delivered sufficient generation to meet demand, and at a reasonable cost. But this report makes it clear that AEMO believes this is no longer the case and that changes to the market are needed.

The report is understandably silent on what this “longer-term approach” might look like, given that market design is tricky. But the report is unequivocal that a new mechanism needs to be in place by the time Liddell closes. If not, supply shortages – and the associated loss of power to consumers – will be far more likely.

AEMO has provided the federal government with a pathway to securing electricity supply for the foreseeable future. There will be costs, but all governments will have greater assurances that the lights will stay on.

What AEMO hasn’t done is call out the policy instability that has been a major reason we have got ourselves into this mess. Commentators, Chief Scientist Alan Finkel, and numerous industry players – including the Big Three owners of generation in Australia – have all long been arguing that the major barrier to investment in the NEM has been the dog’s breakfast that is climate change policy.

The federal government can use this report to satisfy critics within its own party that there is a plan to ensure enough dispatchable generation in the NEM.

But the government must not use AEMO’s report as a get-out clause that allows it to continue to avoid creating an effective emissions reduction policy in the electricity sector. If anything, the report should stand as a stark warning to politicians of all stripes about what happens when you get policy so badly wrong.

Bipartisan agreement on the only politically acceptable emissions reduction policy – a Clean Energy Target – may not be sufficient, but remains absolutely necessary, to ensure there is enough generation to meet Australia’s electricity needs.

The ConversationAEMO has shown it is willing to do its job. It is now up to our politicians to do theirs.

David Blowers, Energy Fellow, Grattan Institute

This article was originally published on The Conversation. Read the original article.

GAZA CONFLICT TAKING TOLL ON BOTH SIDES OF BORDER


Christians normally permitted to leave Gaza for Bethlehem during Christmas found themselves unable to return home and separated from their families when fighting erupted between Israel and Hamas-controlled Gaza in late December, reports Baptist Press.

Isa,* a layman at Gaza Baptist Church, was one of those separated from his family. He returned to Gaza on Dec. 26 to take care of some church business. His family remained in Bethlehem, unaware the borders were about to close. “This is the worst it has ever been [in Gaza],” Isa told a Christian worker.

The Gaza Baptist Church building has sustained damage over the past two weeks. According to a Christian worker, the majority of the damage occurred Dec. 27 when a police station across the street took a direct hit.

Another Christian family found themselves separated when they tried to exit Gaza to find safety in Israel, the Christian worker said. The father and his two sons were allowed to go to Bethlehem, but the wife and two daughters were not. The man quickly returned to Gaza, despite the violence.

Residents of Israel are struggling, too.

One Israeli soldier asked a Christian worker to pray for him while he was at war. To the worker’s surprise, the soldier didn’t ask him to pray for his safety but rather that he wouldn’t have to use his gun.

Life must go on — even in scary situations, the Christian worker added.

A nurse in southern Israel was on her way to a hospital one morning when bomb sirens started blaring. “You can’t stay in your car, because the shrapnel will kill you,” a Christian worker in the area said. “You have to get out of your car and lie in the ditch beside the road.”

Schools in southern Israel have been closed because of bomb threats. Many kindergarten buildings have been hit directly by missile fire from Gaza, a worker said; however, no children or teachers were inside at the time.

“Pray that those who want peace will have the victory,” the worker said. “There’s a lot of praying [among Israeli believers], not only for the soldiers but for the believers in Gaza.”

The hope of Christian workers in Israel is that calm will be restored quickly and that the economy will recover.

Employment in Gaza has plummeted, the worker noted. Twenty years ago nearly 100,000 men went into Israel daily to work; before the latest conflict that number had decreased dramatically. Now, with the border closing, it is down to zero.

Flour has been scarce for more than a week in Gaza — in a culture where bread is served with every meal, the worker said. When a bakery does receive a shipment, it is not uncommon for more than 600 people to line up for the chance to get one piece of flatbread.

Even if families have flour, rotating blackouts make baking nearly impossible, the worker explained. They never know when electricity will be available. Some areas of Gaza haven’t seen power for five days.

Because food, water and electricity are limited in Gaza, Israel is promising to allow aid to reach Palestinian civilians during a three-hour period each day, according to news reports. Food, water, cooking oil and medicine are among the supplies expected to flow into the area.

Report from the Christian Telegraph